Patient specific alignment guide with cutting surface and laser indicator

ABSTRACT

A patient-specific guiding system for guiding an instrument relative to a portion of an anatomical feature of a patient. The patient-specific guiding system includes a patient-specific guide. The guide includes a first portion having a first patient-specific inner surface that conforms to a first surface of the anatomical feature and an outer surface opposite the first patient-specific inner surface. The first portion also includes a guide surface for use in guiding the instrument relative to the anatomical feature. The guide also includes a second portion having a second patient-specific inner surface that conforms to a second surface of the anatomical feature and an outer surface opposite the second patient-specific inner surface. The second portion is removably connected to the first portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 12/389,901, filed Feb. 20, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/211,407, filed Sep. 16, 2008, which is a continuation-in-part of U.S. application Ser. No. 12/039,849, filed Feb. 29, 2008, which: (1) claims the benefit of U.S. Provisional Application No. 60/953,620, filed on Aug. 2, 2007, U.S. Provisional Application No. 60/947,813, filed on Jul. 3, 2007, U.S. Provisional Application No. 60/911,297, filed on Apr. 12, 2007, and U.S. Provisional Application No. 60/892,349, filed on Mar. 1, 2007; (2) is a continuation-in-part U.S. application Ser. No. 11/756,067, filed on May 31, 2007, which claims the benefit of U.S. Provisional Application No. 60/812,694, filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S. application Ser. No. 11/971,390, filed on Jan. 9, 2008, which is a continuation-in-part of U.S. application Ser. No. 11/363,548, filed on Feb. 27, 2006; and (4) is a continuation-in-part of U.S. application Ser. No. 12/025,414, filed on Feb. 4, 2008, which claims the benefit of U.S. Provisional Application No. 60/953,637, filed on Aug. 2, 2007.

In addition, this application is a continuation-in-part of U.S. application Ser. No. 12/486,992, filed Jun. 18, 2009.

Also, this application is a continuation-in-part of U.S. application Ser. No. 12/103,834, filed Apr. 16, 2008, which claims the benefit of U.S. Provisional Application No. 60/912,178, filed Apr. 17, 2007.

This application is also a continuation-in-part of U.S. application Ser. No. 12/483,807, filed on Jun. 12, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/371,096, filed on Feb. 13, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/103,824, filed on Apr. 16, 2008, which claims the benefit of U.S. Provisional Application No. 60/912,178, filed on Apr. 17, 2007.

The disclosures of the above applications are incorporated herein by reference.

FIELD

The following relates to an alignment guide for implantation of a prosthesis and, more particularly, to a patient-specific alignment guide with a cutting surface. The alignment guide may also include a laser indicator.

INTRODUCTION

Various custom made, patient-specific orthopedic implants and associated templates and guides are known in the art. Such implants and guides can be developed using commercially available software. Custom implant guides are used to accurately place pins, guide bone cuts, and insert implants during orthopedic procedures. The guides are made from a pre-operative plan formed from an MRI or CT scan of the patient.

The present teachings provide patient-specific alignment guides that can conveniently and accurately position a cutting tool relative to an anatomical feature.

SUMMARY

A patient-specific guiding system for guiding an instrument relative to a portion of an anatomical feature of a patient is disclosed. The patient-specific guiding system includes a patient-specific guide. The guide includes a first portion having a first patient-specific inner surface that conforms to a first surface of the anatomical feature and an outer surface opposite the first patient-specific inner surface. The first portion also includes a guide surface for use in guiding the instrument relative to the anatomical feature. The guide also includes a second portion having a second patient-specific inner surface that conforms to a second surface of the anatomical feature and an outer surface opposite the second patient-specific inner surface. The second portion is removably connected to the first portion. The first and second patient-specific inner surfaces each have a three dimensional contour that nests and closely conforms to the first and second surfaces, respectively, of the anatomical features, to align the guide relative to the anatomical feature.

Also, a method of guiding an instrument relative to an anatomical feature of a patient is disclosed. The method includes nesting a patient-specific guide that includes a first portion and a second portion on the anatomical feature by fitting a patient-specific inner surface of the first portion to a first surface of the anatomical feature and by fitting a patient-specific inner surface of the second portion to a second surface of the anatomical feature. The method also includes securing the first portion to the anatomical feature, removing the second portion from the first portion, and leaving the first portion secured to the anatomical feature. Furthermore, the method includes guiding the instrument with a guide surface of the first portion relative to the anatomical feature.

Still further, a patient-specific guiding system for guiding an instrument relative to an anatomical feature of a patient is disclosed. The patient-specific guiding system includes a patient-specific guide with a patient-specific inner surface. The patient-specific inner surface has a three-dimensional contour that closely conforms to a surface of the anatomical feature. The patient-specific guide has a guide surface that guides the instrument relative to the anatomical feature. Furthermore, the system includes a laser coupled to the guide that emits a light that identifies a reference plane for use in aligning the guide surface relative to the anatomical feature.

Additionally, a method of guiding an instrument relative to an anatomical feature is disclosed. The method includes nesting a patient-specific guide on the anatomical feature by fitting a patient-specific inner surface of the guide to a surface of the anatomical feature. The guide includes a guide surface that guides the instrument relative to the anatomical feature. The method also includes securing the guide to the anatomical feature, emitting a laser light that identifies a reference plane for use in aligning the guide surface relative to the anatomical feature, and guiding the instrument relative to the reference plane.

Further areas of applicability of the present teachings will become apparent from the description provided hereinafter. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 a perspective view of a patient-specific guiding system having a patient-specific alignment guide according to various exemplary embodiments of the present teachings;

FIG. 2 is a sectional view of the alignment guide of FIG. 1 coupled to an anatomical feature;

FIG. 3 is a sectional view of a portion of the alignment guide of FIG. 1 shown prior to cutting the anatomical feature;

FIG. 4 is a perspective view of the patient-specific alignment guide according to various other exemplary embodiments of the present teachings;

FIG. 5 is a top view of the patient-specific alignment guide according to various other exemplary embodiments of the present teachings;

FIG. 6 is a side view of the alignment guide of FIG. 5;

FIG. 7 is a sectional view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings;

FIG. 8A is a sectional view of the system of FIG. 7 shown prior to cutting an anatomical feature;

FIG. 8B is a top view of the system of FIG. 7 shown with a secondary cutting block mounted to the alignment guide;

FIG. 9 is a sectional view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings;

FIG. 10 is a perspective view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings;

FIG. 11 is a front view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings;

FIG. 12 is a perspective view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings; and

FIG. 13 is a side view of a patient-specific guiding system according to various other exemplary embodiments of the present teachings.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no way intended to limit the present teachings, applications, or uses. For example, although the present teachings are illustrated for alignment guides in knee surgery, the present teachings can be used for other guides, templates, jigs, drills, rasps or other instruments used in various orthopedic procedures.

The present teachings generally provide patient-specific alignment guides and associated cutting guides for use in orthopedic surgery, such as in knee arthroplasty, for example. The patient-specific alignment guides can be used either with conventional or patient-specific implant components prepared with computer-assisted image methods. Computer modeling for obtaining three dimensional images of the patient's anatomy using MRI or CT scans of the patient's anatomy, the patient specific prosthesis components, and the patient-specific guides and templates can be provided by various CAD programs and/or software available, for example, by Materialise USA, Ann Arbor, Mich.

The patient-specific alignment guides are generally formed using computer modeling based on the patient's 3-D anatomic image and have an inner engagement surface that is made to conformingly contact and match a three-dimensional image of the patient's bone surface (with or without cartilage or other soft tissue), by the computer methods discussed above. The patient-specific alignment guides can include custom-made guiding formations, such as, for example, guiding bores or cannulated guiding posts or cannulated guiding extensions or receptacles that can be used for supporting or guiding other instruments, such as drill guides, reamers, cutters, cutting guides and cutting blocks or for inserting pins or other fasteners according to a surgeon-approved pre-operative plan. The patient-specific alignment guides can be used in minimally invasive surgery, and in particular in surgery with multiple minimally-invasive incisions. In one aspect, the cutting guides can include guiding cannulated or tubular legs that can be received in the guiding bores of the alignment guides for cutting therethrough, as discussed below.

The patient-specific alignment guides and the associated cutting guides can be structured to provide or define a clearance for tendons, ligaments or other tissues associated with the joint. In the exemplary illustrations of FIGS. 1-13, various alignment guides and cutting guides can be structured to have specific geometric features for avoiding a tendon associated with the femur or tibia of the knee joint, while enabling the placement of a cutting tool (e.g., blade, drill bit, etc.) as close to the tendon as determined by the surgeon and while maintaining an alignment relative to the joint as determined by the pre-operative surgical plan.

Furthermore, the patient-specific alignment guides can include one or more openings and/or guiding receptacles, the precise location of which are determined on the basis of a pre-operative surgical plan for locating alignment pins and assisting in locating drilling and/or cutting instruments for resecting and shaping the joint for receiving a prosthetic implant, as described in commonly-owned, co-pending in U.S. patent application Ser. No. 11/756,057, filed on May 31, 2007, incorporated herein by reference.

Referring initially to FIG. 1-3 an exemplary embodiment of a patient-specific guiding system 10 will be initially discussed. The system 10 can be used for cutting a portion of an anatomical feature 11 of a patient. It will be appreciated that the system 10 can be used for cutting any suitable anatomical feature 11, such as a bone. Also, it will be appreciated that the system 10 can be used to prepare the anatomical feature 11 for any suitable purpose (e.g., for implantation of an artificial knee joint or other prosthetic device).

As shown in FIG. 1-3, the guiding system 10 can include patient-specific alignment guide 12. The guide 12 can be made out of any suitable material, such as a rigid polymeric material. The shape of the guide 12 can closely conform to a surface of the anatomical feature 11 as will be discussed below. Also, as will be discussed, the guide 12 can locate and align a cutting tool 14 (FIG. 3) or other instruments such as drills, punches, and the like at a predetermined location relative to the anatomical feature 11. As such, the guide 12 locates and aligns the cutting tool 14 for accurate cutting of the anatomical feature 11. It will be appreciated that the cutting tool 14 can be of any suitable type, such as a power tool or a manually operated tool.

The alignment guide 12 can include a first portion 16 (FIGS. 1-3). The first portion 16 can have a relatively thin, plate-like shape. The first portion 16 can include an outer surface 18, an inner surface 20 that is opposite the outer surface 18, and a side surface 22 that extends about the periphery of the first portion 16.

Moreover, the alignment guide 12 can include a second portion 24 (FIGS. 1-2). The second portion 24 can have a relatively thin, plate-like shape. The second portion 24 can include an outer surface 26, an inner surface 28 that is opposite the outer surface 26, and a side surface 30 that extends about the periphery of the second portion 24.

The second portion 24 can be removably connected to the first portion 16. The second portion 24 can be removably connected to the first portion 16 in any suitable fashion. For instance, as shown in FIG. 1, the alignment guide 12 can include a dovetail coupling 32 that removably couples the first and second portions 16, 24. More specifically, the side surface 22 of the first portion 16 can include male components 34 of the dovetail coupling 32, and the side surface 30 of the second portion 24 can include corresponding female components 36 of the dovetail coupling 32. The male components 34 can be removably received within the female components 36 to removably couple the first and second portions 16, 24. Accordingly, as will be discussed, the second portion 24 can be easily removed from the first portion 16 to thereby expose the area of the anatomical feature 11 that will be cut.

As shown in FIG. 2, the first and second portions 16, 24 of the guide 12 can be coupled to the anatomical feature 11. The first and second portions 16, 24 can be configured to be coupled to any suitable anatomical feature 11, such as a femur 38 or other bone.

Specifically, as shown in FIG. 2, the inner surface 20 of the first portion 16 can be patient-specific, such that the inner surface 20 closely conforms in shape to a first surface 40 (e.g., an anterior surface) of the femur 38 of the individual patient. Likewise, the inner surface 28 of the second portion 24 can be patient-specific, such that the inner surface 28 closely conforms in shape to a second surface 42 (e.g., a distal end surface) of the femur 38 of the individual patient. Thus, the inner surfaces 20, 28 can each have three dimensional contours that substantially match the first and second surfaces 40, 42, respectively, and the first and second portions 16, 24 can nest with the first and second surfaces 40, 42. As stated above, the inner surfaces 20, 28 can be shaped according to a computerized model formulated from an imaging process MRI, etc.). Accordingly, the guide 12 can have a customized fit against the femur 38, and cutting of the femur 38 can be performed accurately, according to the individual dimensions of the patient's anatomy.

Furthermore, the first portion 16 can include one or more through holes 44 that extend from the outer surface 18 to the inner surface 20. The precise location of the through holes 44 can be determined on the basis of the pre-operative surgical plan discussed above. Also, the system 10 can include one or more corresponding pins 46 as shown in FIGS. 1 and 2. The pins 46 can extend through corresponding ones of the holes 44 and into the femur 38 to thereby fixedly couple the first portion 16 to the femur 38. It will be appreciated that the second portion 24 can be fixedly coupled to the femur 38 only through the pins 46. Accordingly, the second portion 24 can be easily removed from the first portion 16 and from the femur 38 simply by de-coupling the second portion 24 from the first portion 16, without having to remove other hardware.

Still further, the first portion 16 can include a guide surface, such as an opening 48, as shown in FIGS. 1-3. The precise location of the opening 48 can be determined on the basis of the pre-operative surgical plan discussed above. As will be discussed, the opening 48 can receive the cutting tool 14 (FIG. 3) to guide the cutting tool 14 toward the femur 38 to cut the femur 38 accurately. For example, the opening 48 can be a slot 50 with a straight longitudinal axis that extends substantially parallel to the coupling 32. Also, the slot 50 can extend entirely through the first portion 16 from the outer surface 18 to the inner surface 20. As such, the slot 50 can receive and guide a saw blade 52 (FIG. 3) for making a substantially planar cut along a cutting plane 54. For instance, the cutting plane 54 can be defined on a horizontal plane of the femur 38 to form a distal femoral cut.

It will be appreciated that the opening 48 in the first portion 16 can have any suitable shape to receive and guide any suitable cutting tool 14 other than a saw blade 52. For instance, the opening 48 can be rounded in order to receive a drill bit and to guide the drilling of holes in the femur 38. Also, the opening 48 can have any suitable location on the first portion 16 to guide cutting toward any portion of the anatomical feature 11. For instance, the surgeon can determine a desired location of the cutting plane 54 according to the computerized model discussed above, and the opening 48 can be located on the first portion 16 such that the actual cutting plane 54 closely coincides with the desired cutting plane 54.

It will also be appreciated that the side surface 22 or the outer surface 18 of the first portion 16 can be a guide surface for guiding the cutting tool 14 or other instrument. For instance, the cutting tool 14 or other instrument can abut against the side surface 22, and as such, the cutting tool 14 can be aligned relative to the femur 38. Furthermore, the cutting tool 14 or other instrument can be supported on the outer surface 18 to be aligned relative to the femur 38.

Thus, during use, the first and second portions 16, 24 of the guide 12 can be coupled to the femur 38 that the inner surfaces 20, 28 nest against and engage the femur 38 as shown in FIG. 2. Because both the first and second portions 16, 24 nest against the femur 38, and because the inner surfaces 20, 28 nest against a relatively large surface area of the femur 38, the guide 12 can position and align itself relative to the femur 38 in a highly accurate fashion.

Once the guide 12 is coupled to the femur 38, the second portion 24 can be removed from the first portion 16 (FIG. 3) by pulling the second portion 24 away from the femur 38. This, in turn, exposes the second surface 42 of the femur 38 and allows for better visibility of the femur 38 before cutting. For instance, once the second portion 24 has been removed, the surgeon can visually confirm that the opening 48 will allow the saw blade 52 to cut the femur 38 at a desired location. Furthermore, if the surgeon discovers that the cutting plane 54 needs to be moved, the surgeon can discard the guide 12 and form a new guide 12 with an opening 48 at a different, more desirable location.

Then, the saw blade 52 can be introduced into the opening 48, and the saw blade 52 can cut the femur 38 along the cutting plane 54. As discussed above, the opening 48 can guide movement of the saw blade 52 toward the femur 38 during this cutting operation. Also, since the second portion 24 has been removed, the surgeon can have better visibility of the femur 38 while being cut.

Accordingly, the guide 12 provides a convenient and accurate means for aligning and guiding the saw blade 52 relative to the femur 38 for cutting operations. For instance, separate components, such as separate cut blocks can be unnecessary for cutting since the first portion 16 of the guide 12 includes the opening 48. Moreover, the guide 12 need not be fully removed in order to cut the femur 38. Also, the guide 12 provides substantial visibility of the femur 38 during cutting.

Referring now to FIG. 4, another exemplary embodiment of the patient-specific alignment guide 112 is shown for use within a patient-specific guiding system 110. Features of the guide 112 that correspond to the guide 12 of FIGS. 1-3 are indicated with corresponding reference numerals increased by 100.

The guide 112 can be substantially similar to the guide 12 shown in FIGS. 1-3, except that the first and second portions 116, 124 can be removably coupled to each other via a scored coupling 132. More specifically, the guide 112 can have a scoring line 133 (e.g., a shallow groove) that extends continuously about the guide 112. The scoring line 133 weakens the coupling 132 such that the guide 112 can be easily broken along the scoring line 133, for instance, by manually rotating or pulling the second portion 124 relative to the first portion 116. Thus, in order to remove the second portion 124 from the first portion 116, the surgeon can break the second portion 124 away from the first portion 116 along the scoring line 133. Thus, the coupling 132 can allow for added convenience when removing the second portion 124 from the first portion 116.

Referring now to FIGS. 5 and 6, another exemplary embodiment of the patient-specific alignment guide 212 is shown for use within a patient-specific guiding system 210. Features of the guide 212 that correspond to the guide 12 of FIGS. 1-3 are indicated with corresponding reference numerals increased by 200.

The guide 212 can be substantially similar to the guide 12 shown in FIGS. 1-3, except that the first and second portions 216, 224 can be removably coupled to each other via a pinned coupling 232. More specifically, the first portion 216 can include one or more pins 260 that extend upward from the outer surface 218. The pins 260 can be fixed to the first portion 216. Also, the second portion 224 can include corresponding through holes 262 that removably receive the respective ones of the pins 260. Accordingly, the coupling 232 can allow for added convenience when removing the second portion 224 from the first portion 216.

Referring now to FIGS. 7 and 8A, another exemplary embodiment of the patient-specific alignment guide 312 is shown for use within a patient-specific guiding system 310. Features of the guide 312 that correspond to the guide 12 of FIGS. 1-3 are indicated with corresponding reference numerals increased by 300.

As shown in FIG. 7, the first and second portions 316, 324 of the guide 312 can be substantially similar to the first and second portions 16, 24 of the guide 12 shown in FIG. 1; however, the first portion 316 does not include the opening 22. Instead, the system 310 includes a separate cutting block 366 cutting guide) that includes an opening 368 or other guide surface for guiding and aligning a cutting tool 314 relative to the femur 338. The opening 368 can be a slot, a rounded hole, an edge, or of any other type, similar to the embodiments discussed above. Also, the cutting block 366 can include one or more through holes 369 that removably receive the pin(s) 346 of the guide 312 to removably couple the cutting block 366 to the first portion 316 of the guide 312. It will be appreciated, however, that the cutting block 366 can be removably coupled to the first portion 316 in any suitable fashion (e.g., a dovetail coupling, etc.)

Thus, during use, the guide 312 can be fitted to the femur 338 similar to the embodiments discussed above. Then, the second portion 324 of the guide 312 can be removed. Next, the cutting block 366 can be supported on the outer surface 318 (i.e., the guide surface) of the first portion 316 to align the cutting block 366 relative to the femur 338. The cutting block 366 can be removably coupled to the first portion 316 such that the cutting block 366 is supported on the femur 338 by the first portion 316. As such, the opening 368 can be located and aligned relative to the femur 338 due to the attachment of the cutting block 366 to the first portion 316 of the guide 312. Subsequently, the cutting tool 314 can be introduced into the opening 368, and the opening 368 can guide the cutting tool 314 toward the femur 338 for cutting the femur 338 along the cutting plane 354.

Furthermore, as shown in FIG. 8B, the cutting block 366 can be removed from the first portion 316, and a secondary cutting block 366′ (e.g., a Four-in-One cutting block commercially available from Biomet of Warsaw, Ind.) can be removably coupled to the first portion 316 for performing additional cutting of the femur 338. More specifically, the secondary cutting block 366′ can include through holes 369′ that removably receive the pins 346 such that the first portion 316 aligns the secondary cutting block 366′ at a predetermined position relative to the femur 338. The secondary cutting block 366′ can also include a respective opening 368′ for guiding the cutting tool 314 while cutting along a secondary cutting plane 354′. For instance, the secondary cutting block 366′ can be used for forming an anterior femoral cut, a posterior femoral cut, or a femoral chamfer cut.

Also, in some embodiments, the pins 346 and/or the first portion 316 can obstruct this additional cutting of the femur 338. Thus, as shown in FIG. 8B, after the secondary cutting block 366′ is coupled to the first portion 316 via the pins 346, one or more secondary pins 346′ can be used to couple the secondary cutting block 366′ to the femur 338. Next, the pins 346 and the first portion 316 can be removed from the femur 338, leaving the secondary cutting block 366′ coupled to the femur 338 via the secondary pins 346′. Then, the cutting tool 314 can be received in the opening 368′ to cut the femur 338 along the secondary cutting plane 354′, and the secondary pins 346′ are unlikely to obstruct the cutting tool 314. Thus, the guide 312 can be versatile for supporting and aligning a plurality of cutting blocks 366, 366′ relative to the femur 338.

Referring now to FIG. 9, another exemplary embodiment of the patient-specific system 410 is shown. Features of the system 410 that correspond to the system 310 of FIGS. 7-8B are indicated with corresponding reference numerals increased by 100.

The system 410 is substantially similar to the system 310 of FIGS. 7-8B, except that the cutting block 466 is removably coupled to the first portion 416 of the guide 412 via a snap-fit coupling 432. For instance, the cutting block 466 can include one or more openings 470, each with a plurality of resilient members 472. For instance, the openings 470 can be rounded and can have a shape that corresponds to the pins 446. The resilient members 472 can be spaced apart at a width W that is less than a width W′ of one of the pins 446.

Thus, to removably couple the cutting block 466 to the guide 412, the cutting block 466 is moved toward the pins 446, and the resilient members 472 resiliently deflect to allow passage of the respective pin 446 into the respective opening 470. Then, to remove the cutting block 466, the resilient members 472 can resiliently deflect to allow passage of the respective pin 446 out of the respective opening 470. Thus, the snap-fit coupling 343 can allow for quick and convenient coupling and de-coupling of the cutting block 466 and the guide 412.

Referring now to FIG. 10, another exemplary embodiment of the patient-specific system 510 is shown. Features of the system 510 that correspond to the system 310 of FIGS. 7-8B are indicated with corresponding reference numerals increased by 200.

The system 510 is substantially similar to the system 310 of FIGS. 7-8B, except that the system 510 can include one or more spacers 578 a, 578 b that can be disposed between the cutting block 566 and the first portion 516 of the guide 512. The spacers 578 a, 578 b can be relatively flat and thin (e.g., 1 mm thickness) plates. The spacers 578 a, 578 b can space the cutting block 566 and the guide 512 apart at a predetermined distance. For instance, before cutting, the surgeon may wish to adjust the position of the opening 568 relative to the femur. Thus, the surgeon can include one or more spacers 578 a, 578 b between the cutting block 566 and the first portion 516 to move the opening 568 the desired distance relative to the femur. In the embodiment shown, for instance, the surgeon can include additional spacers 578 a, 578 b in order to move the opening 568, and thus the cutting plane, distally along the femur. Thus, the system 510 can be modular and versatile for cutting the anatomy at desired locations.

Moreover, as shown in FIG. 10, the cutting block 566 and the first portion 516 of the guide 512 can be removably coupled via a magnetic coupling 532. For instance, the first portion 516 can include one or more magnets 574, and the cutting block 566 can also include one or more corresponding magnets 576 that are magnetically attracted to the magnets 574. In other embodiments, only the magnets 574 are included, and the magnets 574 are magnetically attracted to the material of the cutting block 566. In other embodiments, only the magnets 576 are included, and the magnets 576 are magnetically attracted to the material of the first portion 516. It will be appreciated that the magnetic attraction of the magnets 574, 576 is sufficient enough to couple the cutting block 566, the spacers 578 a, 578 b, and the first portion 516 if the spacers 578 a, 578 b are included. Accordingly, the magnetic coupling 532 can provide for convenient coupling and de-coupling of the cutting block 566 and the first portion 516.

Referring now to FIG. 11, another exemplary embodiment of the guide 612 is illustrated. Features of the guide 612 that correspond to the guide 12 of FIGS. 1-3 are indicated with corresponding reference numerals increased by 600.

As shown in FIG. 11, the guide 612 is patient-specific and is shaped to conform to a tibia 680 of the patient. As such, the guide 612 includes three dimensional contoured surfaces that nest against and conform to the tibia 680, similar to the embodiments discussed above. The guide 612 can include a first portion 616 that fits on an anterior surface of the tibia 680 and a second portion 624 that fits on a proximal end surface of the tibia 680. The guide 612 can be used for cutting the tibia 680 along a cutting plane 654 (e.g., a horizontal tibial cut).

The guide 612 can also include a laser 682. In some embodiments, the laser 682 is embedded within the guide 612; however, in some embodiments, the laser 682 can be removably coupled to the guide 612. The laser 682 can be of any suitable type, and the laser 682 can emit light along a path 684 to identify a reference plane for use in aligning a guide surface of the guide 612 and for confirming that the guide surface is at a desired location relative to the tibia 680. As such, the emitted light can indicate where the cutting tool will cut the tibia 680 prior to the cutting operation in order to confirm that the tibia 680 will be cut at a desired location.

For instance, the reference plane indicated by the laser 682 can be directed along a path 684 that is substantially perpendicular to the longitudinal axis of the opening 648. Since the axis of the opening 648 defines the cutting plane 654, the path 684 of the light becomes substantially perpendicular to the cutting plane 654.

Thus, during use, the guide 612 can be coupled to the tibia 680 as described above with respect to FIGS. 2 and 3. Next, the laser 682 can be operated to emit light along the path 684. For instance, the laser 682 can emit a dot of light that is reflected off of a reference point (e.g., one of the metatarsals 686) of the patient. If the light is substantially centered on the reference point, (e.g., the second metatarsal 686), the surgeon knows that the cutting plane 654 is substantially perpendicular to the major axis of the tibia 680. If the light is spaced apart from the reference point, the surgeon knows that the cutting plane 654 may need to be adjusted. Other reference points other than the second metatarsal 686 can be used to confirm that the cutting plane 654 is properly aligned relative to the tibia 680 as well. Accordingly, the guide 612 allows for convenient and accurate confirmation of the alignment of the cutting plane 654 before cutting is performed.

It will be appreciated that the laser 682 can be directed along any path 684 relative to the guide 612. For example, the reference plane indicated by the path 684 of the laser 682 can be at a positive, acute angle relative to the longitudinal axis of the opening 648 (i.e., at a positive, acute angle relative to the cutting plane 654). This may be useful, for instance, for indicating specific anatomy that is disposed at an angle relative to the cutting plane 654 and/or for adjusting the cutting plane 654 relative to that anatomy.

Referring now to FIG. 12, another exemplary embodiment of the guide 712 is illustrated. Features of the guide 712 that correspond to the guide 612 of FIG. 11 are indicated with corresponding reference numerals by 100. As before, the guide 712 can include three-dimensional contoured surfaces that nest against and conform to the tibia 780.

As shown in FIG. 12, the laser 782 can include a first end 783 and a second end 785. The laser 782 can be coupled to the first portion 716 of the guide 712 such that the first and second ends 783, 785 are both angled toward the tibia 780. Also, the first and second ends 783, 785 can emit light in a straight line that is disposed within the cutting plane 754. As such, the surgeon can use the laser 782 to illuminate a proposed cutting plane/line on the tibia 780. Thus, the surgeon can confirm that the cutting plane 754 is at a desired location relative to the tibia 780.

Referring now to FIG. 13, another exemplary embodiment of the system 810 is illustrated. Features of the system 810 that correspond to the system 610 of FIG. 11 are indicated with corresponding reference numerals increased by 200.

As shown in FIG. 13, the laser 882 can be removably coupled to the cutting block 866. For instance, the system 810 can include a fixture 890 that removably couples to both the laser 882 and the cutting block 866. In other embodiments, the fixture 890 can directly couple the laser 882 to the first portion 816 of the guide 812.

The laser 882 can emit light in a line that is directed along a path that is substantially perpendicular to the cutting plane 854. Thus, similar to the embodiment of FIG. 11, the laser 882 can help the surgeon to confirm that the cutting plane 854 is at a desired location relative to the tibia 880.

In summary, the patient-specific guiding system 10-810 discussed herein provides for accurate and convenient alignment of the cutting tool 14-814 relative to the anatomy because the guide 12-812 has three dimensional surfaces that closely conform to respective surfaces of the anatomy of the patient. Furthermore, the guide 12-812 can include first and second portions that are removably coupled (e.g., via a dovetail coupling 32, a pinned coupling 232, a scored coupling 132, a magnetic coupling 532, a snap-fit coupling 432, etc.) such that the anatomy has a high degree of visibility before and during cutting. Moreover, the guide 12-812 can include an opening 48-848 or other guide surface that guides the cutting tool 14-814 for accurate and convenient cutting. Also, in some embodiments, the guide 12-812 can removably couple to a separate cutting block 366, 466, 566, 866 (e.g., via a dovetail coupling 32, a pinned coupling 232, a scored coupling 132, a magnetic coupling 532, a snap-fit coupling 432, etc.), and the cutting block 366, 466, 566, 866 can include the opening 368, 468, 568 for guiding the cutting tool 314, 414, 514 for accurate cutting. As such, the system 10-810 can allow the anatomy to be cut more accurately, and a prosthetic device can be better customized for the patient.

The foregoing discussion discloses and describes merely exemplary arrangements of the present teachings. Furthermore, the mixing and matching of features, elements and/or functions between various embodiments is expressly contemplated herein, so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the spirit and scope of the present teachings as defined in the following claims. 

What is claimed is:
 1. A patient-specific guiding system for guiding an instrument relative to a portion of an anatomical feature of a patient, the patient-specific guiding system comprising: a patient-specific guide having: a first portion having a first patient-specific inner surface that is configured to conform to a first surface of the anatomical feature and an outer surface opposite the first patient-specific inner surface, the first portion including a guide surface for use in guiding the instrument relative to the anatomical feature; a second portion having a second inner surface that is configured to conform to a second surface of the anatomical feature and an outer surface opposite the second inner surface, the second portion being removably connected to the first portion; and a fixation feature that is configured to be coupled to the first portion directly to the anatomical feature the fixation feature comprising a pair of pin holes spaced apart along a length of the guide surface; wherein the second portion is configured to be coupled to the anatomical feature through the coupling mechanism via attachment to the first portion; and wherein the first patient-specific inner surface has a three dimensional contour that is configured to nest and closely conform to the first surface of the anatomical feature, to align the guide relative to the anatomical feature.
 2. The patient-specific guiding system of claim 1, wherein the second portion is removably connected to the first portion by a coupling mechanism comprising at least one of a dovetail coupling, a pinned coupling, a scored coupling, a magnetic coupling, and a snap-fit coupling.
 3. The patient-specific guiding system of claim 1, wherein the guide surface is an opening that receives the instrument.
 4. The patient-specific guide of claim 2, wherein the coupling mechanism comprises a snap-fit coupling.
 5. The patient-specific guide of claim 4, wherein the first surface comprises an anterior surface of a distal portion of a femur.
 6. The patient-specific guide of claim 5, wherein the coupling mechanism is configured to release the second portion from the first portion in a direction extending in a superior-to-inferior direction relative to an axis of the femur.
 7. The patient-specific guide of claim 5, wherein the second surface comprises a second patient-specific surface having a three dimensional contour that is configured to nest and closely conform to the second surface of the anatomical feature to align the guide relative to the anatomical feature, the second surface comprising a distal surface of a distal portion of the femur.
 8. The patient-specific guide of claim 5, wherein: the second portion engages the first portion on an anterior side of the femur; and the guide surface is oriented to remove a distal surface of the distal portion of the femur.
 9. The patient-specific guide of claim 5, wherein the first patient-specific inner surface extends contiguously across the anterior surface in a medial-lateral direction.
 10. A method of guiding an instrument relative to an anatomical feature of a patient comprising: coupling a first portion of a patient-specific guide to a second portion of the patient-specific guide; fitting a patient-specific inner surface of the first portion to a first surface of the anatomical feature to thereby position the second portion relative to a second surface of the anatomical feature; securing the first portion to the anatomical feature; removing the second portion from the first portion; leaving the first portion secured to the anatomical feature; and guiding the instrument with a guide surface of the first portion relative to the anatomical feature.
 11. The method of claim 10, wherein securing the first portion comprises pinning the first portion to the anatomical feature.
 12. The method of claim 10, wherein the guide surface is slot that receives the instrument.
 13. The method of claim 10, wherein removing the second portion from the first portion comprises: releasing a snap-fit coupling; and pulling the second portion from the first portion in proximal-to-distal direction.
 14. The method of claim 13, wherein releasing the snap-fit coupling comprises deflecting a feature of the second portion to allow the second portion to be released from the first portion.
 15. The method of claim 10, wherein guiding the instrument with a guide surface of the first portion relative to the anatomical feature further comprises removing a distal portion of a distal end of a femur with the instrument.
 16. A cutting guide for performing a distal resection of a femur, the cutting guide comprising: a first guide body portion comprising: a patient-specific surface configured to mate with an anterior surface of a distal end of the femur; a first outer surface opposite the patient-specific surface; and a cutting guide surface extending through the first guide body portion from the first outer surface to the patient-specific surface; a second guide body portion comprising: an inner surface configured to mate with a distal surface of the distal end of the femur; and a second outer surface opposite the inner surface; and a snap-fit coupling configured to connect the first and second guide bodies.
 17. The cutting guide of claim 16, wherein the snap fit coupling comprises a pair of deflectable features on the second guide body portion that are configured to bend to release the second guide body portion from the first guide body portion in a proximal-distal direction.
 18. The cutting guide of claim 16, further comprising a pair of pin holes spaced apart on the first guide body portion along a length of the cutting guide surface. 